The above disk reproducing apparatus is known, for example, from Japanese Laid Open Patent Application No. 60856/1989 (Tokukaisho 64-60856). As shown in FIG. 47, the disk reproducing device includes two disk trays 52 and 53 (hereinafter referred to as first and second trays) inside a cabinet 51 which forms a housing for the apparatus. The first and second trays 52 and 53 can reciprocate from side to side (in directions shown by arrows L and R in FIG. 47).
In FIG. 47, the left half of the apparatus is formed as a reproducing area wherein a turn table 54 and an optical pickup 55 are mounted, while the right half of the apparatus is formed as a stand-by area. In the stand-by area, the disk can be set on and removed from the disk tray 52 or 53 as desired. The first and second trays 52 and 53 are placed so as to be vertically aligned with a predetermined space between them. The first tray 52 and the second tray 53 are interchangeable between the reproducing area and the stand-by area as they move respectively along the lower horizontal movement guide rail and the upper horizontal movement guide rail.
On the underside of the first and second trays 52 and 53, a sliding plate 56 and a cam disc 57 are mounted. On the cam disc 57, a first cam groove 57a is formed for inserting a follower pin 56a of the sliding plate 56 so as to be fit therein. The sliding plate 56 has racks 56b respectively formed on both side faces in the front-and-back direction (in directions shown by arrows F and B in FIG. 48). Further, a pair of small pinions 58a are mounted to the racks 56b so as to be respectively in mesh therewith. Around each small pinion 58a, a large pinion 58b is coaxially and integrally formed.
As shown in FIG. 49, on the underside of the first tray 52 and on both side faces of the second tray 53 in the front-and-back direction, a pair of racks 52a and a pair of racks 53a are respectively formed side to side. The apparatus is assembled such that each large pinion 58b is provided between the rack 52a and the rack 53a in the front-and-back direction so as to be in mesh therewith.
As shown in FIG. 50, on the underside of the cam disk 57, a second cam groove 57b is formed. Further, a connecting plate 59 with a follower pin 59a which makes a possible mating with the second cam groove 57b is provided. The front and back ends of the connecting plate 59 are respectively connected to actuating plates 60 placed vertically to both sides of the reproducing area. A reproducing unit 61, in which a turn table 54 and an optical pickup 55 are mounted, holds support pins 61a respectively projected outward from the front and rear sides of the reproducing unit 61 by inserting them into guide grooves 60a formed on the actuating plate 60 as shown in FIG. 51.
In the described arrangement, when reproducing from the disk on the second tray 53 set in the stand-by position, the second tray 53 in this position and the first tray 52 in the reproducing area are switched by rotating the cam disc 57.
With the rotations of the cam disk 57, first, the follower pin 59a of the connecting plate 59 is pressed by the second cam groove 57b. This, in turn, moves the actuating plates 60 side to side. As a result, along the sloping guide groove 60a of the actuating plate 60, the support pin 61a is pressed downward, and the reproducing unit 61 is lowered, thereby holding the turn table 54 and the optical pickup 55 in respective retreated positions, i.e., in positions lower than the position of the first tray 52.
Subsequently, with the rotations of the cam disc 57, the follower pin 56a of the sliding plate 56 which makes a possible mating with the first cam groove 57a is pushed. This, in turn, moves the sliding plate 56 side to side. In accordance with this movement, the small and large pinions 58a and 58b are rotated. In this state, as the large pinion 58a is in mesh with the racks 52a and 53a, the first and second trays 52 and 53 are moved horizontally in directions opposite one another.
After the respective positions of the trays 52 and 53 are switched by moving them side to side in the described manner, the reproducing unit 61 is raised again in synchronism with the movement of the actuating plates 60 so as to enable a reproducing operation from the disk on the second tray 53 set in the reproducing area, thereby completing the tray interchanging operation.
However, in such a conventional disk reproducing apparatus, since the trays are interchanged only by moving the first and second trays 52 and 53 horizontally along paths formed at different height positions, the problem is presented in that a long stroke of the up-and-down movement of the reproducing unit 61 is required. More specifically, in the tray interchanging operation, the reproducing unit 61 is lowered to the retreated position, i.e., the position lower than the first tray 52, while in reproducing, the turn table 54 is raised to the reproducing position, i.e., the position higher than the second tray 53 in the upper position so that the disk can rotate. Therefore, the stroke of the movement between the retreated position and the reproducing position becomes longer in accordance with the respective height difference of the first and second trays 52 and 53. Since this makes the apparatus thicker, the size of the apparatus cannot be made any smaller.